With a SWG, CH should be kept between 350 to 450. Calcium helps fiberglass pools resist staining and cobalt spotting....Is this correct as I read somewhere else on here fibreglass SWG 220-300....current SWG fibreglass pool is CH 225....and some staining so was hoping this may be the cause? Cheers
Calcium
- Thread starter AussieSwimmer
- Start date
Brad_C
Well-known member
- Nov 15, 2018
- 188
- Pool Size
- 19000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Monarch ESC24 / ESC7000
My CH sat at about 90 for years. I suspect that is a significant part of the issue with the degredation of the gelcoat as it's still relatively good above the waterline. I now have it up about 260. Too late for my glass however.
What sort of staining are you seeing? I have a couple of beaut little rust squares where one of my boys chucked a few cheap galv nuts in the pool and I didn't notice before we went on holidays.
What sort of staining are you seeing? I have a couple of beaut little rust squares where one of my boys chucked a few cheap galv nuts in the pool and I didn't notice before we went on holidays.
- Jun 22, 2014
- 47,979
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
For a FB pool, TFP recommends a CH between 220-320. Most pools today have no calcium in the manufacture process, so some FB owners get-by with a slightly lower CH without adverse effects. In your case however, the true source of any staining is what really needs to be asessed to try and prevent recurrance. Do you have any idea what the staining may be from?
Trouble Free Pool
Trouble Free Pool
I'm very new to pool maintenance, recently done my first SLAM. Black marks started before that though. Small little black marks that don't scrub off and larger black patches that look as if fibreglass has faded but I'm assuming it's some kind of stain.
TA is very high, in the process of trying to fix that but struggling to get FC below 10, I've been a bit paranoid with such hot weather I've put my SWG on at times as I'm terrified off FC dropping low and Algae returning, I'm still learning how to maintain a good level under 10ppm. CYA is 75.
I'm really hoping I can fix this as pool is looking great post SLAM.
TA is very high, in the process of trying to fix that but struggling to get FC below 10, I've been a bit paranoid with such hot weather I've put my SWG on at times as I'm terrified off FC dropping low and Algae returning, I'm still learning how to maintain a good level under 10ppm. CYA is 75.
I'm really hoping I can fix this as pool is looking great post SLAM.
Attachments
- Jun 22, 2014
- 47,979
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
You noted your current CH is about 225, CYA 75, and FC a bit over 10. What is your pH and TA?
Couple other questions;
- How old is your pool if you know?
- Have you added any other products to the water other than salt and perhaps muriatic acid?
Couple other questions;
- How old is your pool if you know?
- Have you added any other products to the water other than salt and perhaps muriatic acid?
pH I'm not sure, assuming it's high, potentially 8+ due to TA of 250ppm.
Salt, Acid, liquid chlorine and stabilizer.....before I found this wonderful site, a fair bit of Algaecide.
Salt, Acid, liquid chlorine and stabilizer.....before I found this wonderful site, a fair bit of Algaecide.
- Jun 22, 2014
- 47,979
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
It's possible you have a couple issues happening. For example, we know and excessively high pH and TA can lead to calcium scale, even in our FB pools. An elevated pH is also known to aggrevate metals in water. Scale can have a chalky look, but on some finishes can also present and disolored, tarnished appearance. You'll want to use your CCL test kit to verify your pH and lower it to the mid-7s right away. We also know that algaecides commonly contain copper. When enough product is used over time, it can stain pool surfaces as well. A copper test kit can be a bit pricey. While we don't normally advise using a pool store for water testing, they usually include metals testing. You might consider taking a sample to a local shop just to see what iron/copper levels they may show if any.
I need to get my FC well below 10 then to get accurate pH results. It's going to be very hot tomorrow, if I left my SWCG off with CYA off 75, will the FC drop be safe?
Cheers for advice. So in a nutshell get pH sorted before potentially raising Calcium or can I do both at once?
Cheers for advice. So in a nutshell get pH sorted before potentially raising Calcium or can I do both at once?
- Jun 22, 2014
- 47,979
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
I would let the pH fall to 10 before confirming/adjusting the pH. But if the pH is indeed high, lower it to the mid-7s for sure. No need to add anymore CH. At your current level it should be fine. Also consider lowering your TA if it is as high as you anticipate. You can review the TFP Trouble Free Pool for tips on lowering TA.
Just in case those stains are something else, you migh try to the following tests just to rule-out the easy stuff:
- Rub a chlorine tab/puck on the area; if it lightens, it was an organic stain
- Place some crushed Vitamin C tabs in a thin sock or nylon and rub a stain. If it lightens it is iron. It it gets darker, it's probably copper.
Just in case those stains are something else, you migh try to the following tests just to rule-out the easy stuff:
- Rub a chlorine tab/puck on the area; if it lightens, it was an organic stain
- Place some crushed Vitamin C tabs in a thin sock or nylon and rub a stain. If it lightens it is iron. It it gets darker, it's probably copper.
- May 3, 2014
- 58,745
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
As long as you are using the pH kit with the Taylor R-0014 reagent unless you are way above FC of 10 ppm your pH reading will be accurate as long as you read the color match quickly after adding the reagent.
What is your FC level?
What is your FC level?
FC is currently 12ppm....the other day it was 9 and I tested pH and it was 7.8...I added 1.5L of acid (in 3 goes) and noticed only a very minor change in pH result. Got spooked out of doing any more as thought perhaps the FC level was affecting my results. Maybe I should have persisted with adding acid at that point.
- May 3, 2014
- 58,745
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
At a FC of 12 ppm your pH test will not be that effected unless you let it sit for quite some time.
Doe your SWCG shed calcium flakes when it reverses polarity?
Doe your SWCG shed calcium flakes when it reverses polarity?
- Jun 22, 2014
- 47,979
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
That could depend on what exactly the staining is from. If it's on the surface, local treatment might work well. If it's something that became embedded in the gelcoat or actually discolored the gelcoat somehow, that's a different story. Was this a new pool to you? Do you know the age?
- May 3, 2014
- 58,745
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
The SWCG reverses polarity every so many hours. When it does that, any calcium scale buildup on the plates are shed. I can tell my TA and/or pH are getting higher just by the calcium scale being shed. Happens whether my CH is 300 or 800 ppm. My CH rises over a 12+ month period due to evaporation and high CH fill water.
- May 3, 2014
- 58,745
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Those are from the SWCG. I focus on keeping my CSI at or near -0.3 and it minimizes the occurrence.